The California-Mexico border is one of the most active drug
smuggling corridors along the U.S.-Mexico border. Mexican DTOs
smuggle large quantities of cocaine, heroin, marijuana, and
methamphetamine through California POEs destined for wholesale
markets within the CBAG region and throughout the United States.
Illicit drugs are generally transported in private and commercial
vehicles, typically concealed in hidden compartments or in cargo
shipments; however, sometimes they are transported openly on the
seat or in the trunk of a vehicle. Cocaine, heroin, and
methamphetamine seizures at the San Diego and El Centro POEs
increased from 2005 through 2006. CBP data indicate that the amount
of cocaine seizures increased 72 percent from 2005 through 2006;
heroin seizures increased 102 percent; and methamphetamine, 55
percent. There was a 14 percent decrease in the amount of marijuana
seized at POEs from 2005 through 2006. (See Table
2.) Mexican DTOs primarily use Interstates 5, 8, 15, and 805 as
principal trafficking routes through and from the CBAG region.
Additionally, Mexican DTOs use I-5 and I-15 to connect to I-10, an
east-west highway that traverses the southern portion of the United
States from Barstow, California, to Jacksonville, Florida.

Table 2. U.S. Customs and Border Protection Drug Seizures, by Drug,
in Kilograms, San Diego and El Centro Sectors, 2004-2006

Drug

2004

2005

2006

Marijuana

87,973

111,535

95,373

Cocaine

1,997

2,287

3,934

Heroin

69

46

93

Methamphetamine

368

864

1,343

Source: U.S. Customs and
Border Protection, as of June 5, 2007.

Mexican DTOs also smuggle illicit drugs through remote areas
between POEs along the
California-Mexico border. Traffickers often use backpackers, private
vehicles, and all-terrain vehicles while smuggling drugs between
POEs, particularly in traversing the mountainous areas in eastern
San Diego County and the desert and sand dune areas in Imperial
County. Drug seizures between POEs dramatically increased from 2005
to 2006. U.S. Border Patrol data indicate that the amount of
marijuana seizures increased 64 percent from 2005 through 2006;
cocaine seizures increased 120 percent; heroin, 234 percent; and
methamphetamine, 94 percent. (See Table 3.)

According to law enforcement officials, the number of
subterranean tunnels used by Mexican DTOs through which to smuggle
drugs into the United States is increasing. Approximately 31 tunnels
have been discovered along the California-Mexico border since
1993--15 were discovered in 2006 alone. Law enforcement reporting
indicates that one of the tunnels was accidentally discovered when a
law enforcement vehicle fell into a passageway. Use of subterranean
tunnels is mostly limited to large-scale Mexican DTOs because they
have the resources and influence needed to organize, fund, and
construct these tunnels. Despite increased use of subterranean
tunnels by Mexican DTOs, marijuana has been the only drug seized
from tunnel operations along the California-Mexico border; however,
given the polydrug nature of Mexican DTOs, it is quite likely that
most drugs trafficked by Mexican DTOs have, at one time or another,
been smuggled to the United States through tunnels. Moreover,
subterranean tunnels may pose a distinct security threat to the
country because they are a potential means by which terrorists can
enter--or smuggle weapons into--the United States. Law enforcement
officials believe that DTOs increased their use of tunnels after
enhanced border security measures were implemented following the
September 11, 2001, terrorist attacks.

Mexican DTOs may also use air and rail conveyances to smuggle
illicit drugs into the CBAG region from Mexico. San Diego and
Imperial Counties have 48 airstrips recognized by the Federal
Aviation Administration and numerous, privately owned, "soft
surface" runways, which can be used by low-flying aircraft
attempting to avoid radar detection to smuggle illicit drugs into
the region. A San Diego County park ranger from the Agua Caliente
County Park (an area long popular with drug smugglers) noted
significant clandestine air activity at the Agua Caliente airfield.
The ranger also noticed on several occasions that both ends of the
runway had burn marks in the asphalt, and there was evidence that
flares had been used. The potential for rail smuggling exists at the
Calexico and San Ysidro POEs, which have the only POE rail crossings
on the California-Mexico border. Law enforcement officials report
that traffickers often use spotters to monitor rail traffic
traversing the U.S.-Mexico border. Individuals conducting
surveillance, equipped with Nextel push-to-talk phones, have been
observed on the U.S. side of the Calexico POE, positioned a short
distance from locations at which trains enter the United States from
Mexico.

Mexican DTOs use recreational and commercial watercraft to
smuggle illicit drugs into the region along coastal areas, including
the San Diego Bay and surrounding bays and harbors. Maritime
smuggling operations into southern California often originate from
Rosarito Beach, Popotla Beach, and La Salina Beach in northern Baja
California, Mexico. Mexican vessels departing from these locations
regularly travel to the Coronado Islands off the coast of Baja
California, where they offload drug shipments to U.S.-registered
pleasure craft that transport the shipments into the San Diego area,
often blending with legitimate maritime traffic. Additionally, the
Port of San Diego handles cargo shipments from illicit drug source
countries and transit areas, including Mexico, Central and South
America, and Asia, particularly South Asia. U.S. law enforcement
authorities often seize illicit drugs from commercial vessels that
cross the Eastern Pacific Ocean, originating in countries from these
areas en route to the Port of San Diego or nearby locations. For
instance, during fiscal year (FY) 2005, the latest year for which
data are available, approximately 300,000 pounds of cocaine were
seized in the Eastern Pacific, an increase of 25 percent from
FY2004.